Why are some papers dry off the printer while others take minutes to hours to dry?
A. There are basically 2 technologies used in high end papers, swellable and micropore. Swellable is the older technology used with the first Encad and HP thermal printers. A gelatin layer was used to “swell” when the water based ink made contact, then dried to form a protective barrier form atmospheric contaminants. Unfortunately, the gelatin is susceptible to all forms of moisture, and are unstable in a high humidity environment, or even a sweaty finger will ruin the print. With the obvious disadvantage of swellable papers evident, research progressed from gelatin to silica. The silica coatings formed small pores that trapped the ink, letting the water evaporate quickly. This led to the “Instant Dry” and “Water Resistant” media. Most media today are micropore except for some low end signage papers that are cost effective. Note, there is one major disadvantage with instant dry papers, atmospheric contaminants. These coatings offer no protection from ozone or other airborne contaminant
